"He's done an unbelievable job as a Mariner, and certainly I don't take any of this lightly," Servais said. "But I just think trying to make the best decisions for the ballclub, and really for Felix at this point, let's just take a breath, step back, gather yourself."

The move comes after Hernandez's abysmal start against the Texas Rangers on Tuesday, when the right-hander allowed 11 runs - seven earned - on eight hits and four walks, while striking out two. The disastrous outing swelled his ERA to 5.73.

"I've got nothing to say," Hernandez replied when asked about the change.

Over his 14-year major-league career, Hernandez has never made an appearance out of the bullpen.

He's had trouble recapturing his Cy Young form from 2010. Since his age-30 season in 2016, the six-time All-Star owns a 4.60 ERA and 4.86 FIP over 64 games.